Search Publications
Statistical altitude distribution of Cluster auroral electric fields, indicating mainly quasi-static acceleration below 2.8 RE and Alfvénic above
Karlsson, T.; Li, B.; Masson, A. +3 more
Results are presented from a statistical study of high-altitude electric fields and plasma densities using Cluster satellite data collected during 9.5 years between 2 and 4 RE. The average electric fields are most intense on the nightside and associated with an extensive plasma density cavity, with densities of 1 cm-3 or less…
Kinetic model of Janaki et al.'s bifurcated current sheet
Dasgupta, B.; Yoon, P. H.; Janaki, M. S.
Space satellite observations show that current sheets in the space plasma environment are often characterized by bifurcated structures. In a recent paper a two-fluid model of the bifurcated current sheet was constructed on the basis of the pseudo potential method. A straightforward generalization of Janaki et al.'s two-fluid model to kinetic forma…
Contrasting electron acceleration processes during two substorms
Schriver, David; El-Alaoui, Mostafa; Walker, Raymond J. +3 more
Although energetic particle injections during substorms have been observed near geosynchronous orbit since the late 1960s, how the injected particles are accelerated during a substorm is still not fully understood. Studies show that injections are associated with earthward propagating dipolarization fronts and suggest that particle acceleration ca…
Effect of plasma torus density variations on the morphology and brightness of the Io footprint
Crary, F.; Payan, A. P.; Rajendar, A. +1 more
We develop a 2-D-layered model of the Io plasma torus to study the apparent "shutoff" of the Io footprint in 2007, when it disappeared beneath a region of diffuse emissions, roughly coincident with a massive eruption of Tvashtar Paterae. First, we investigate the effects of Io's location in the plasma torus and validate our model results against H…
Analytical model of rotating two-cell convection at Saturn
Waite, J. H.; Burch, J. L.; Hill, T. W. +1 more
We use an analytical model of magnetosphere-ionosphere coupling to show that an asymmetric ring current (RC) pressure with an m=1 longitudinal dependence can initiate a rotating two-cell interchange potential. The model extends prior similar work by considering both cold plasma interchange and warm plasma pressure. This model predicts that within …
Separating drivers of Saturnian magnetopause motion
Dougherty, M. K.; Masters, A.; Sulaiman, A. H. +2 more
Surface waves on Saturn's magnetopause and oscillations of the magnetopause at a period associated with that of planetary rotation have previously been detected. How the amplitudes of these two key perturbations to the magnetopause position compare, however, is unclear. We construct a one-dimensional magnetopause model that considers both types of…
Outflow and plasma acceleration in Titan's induced magnetotail: Evidence of magnetic tension forces
Kurth, W. S.; Leblanc, F.; Edberg, N. J. T. +11 more
Cassini plasma wave and particle observations are combined with magnetometer measurements to study Titan's induced magnetic tail. In this study, we report and analyze the plasma acceleration in Titan's induced magnetotail observed in flybys T17, T19, and T40. Radio and Plasma Wave Science observations show regions of cold plasma with electron dens…
Collisionless resistivity in a bifurcated current sheet
Andriyas, T.; Spencer, E.
The collisionless resistivity due to charged particle chaos in spatially inhomogeneous magnetic fields is calculated for two frequently observed magnetotail current sheets, the X line, and a bifurcated current sheet (BCS) over varying strengths of cross-tail electric field. The calculation is done for two charged species, protons and O+…
Surface current balance and thermoelectric whistler wings at airless astrophysical bodies: Cassini at Rhea
Khurana, K. K.; Waite, J. H.; Teolis, B. D. +1 more
Sharp magnetic perturbations found by the Cassini spacecraft at the edge of the Rhea flux tube are consistent with field-aligned flux tube currents. The current system results from the difference of ion and electron gyroradii and the requirement to balance currents on the sharp Rhea surface. Differential-type hybrid codes that solve for ion veloci…
Local time dependences of oxygen ENA periodicities at Saturn
Mitchell, D. G.; Carbary, J. F.; Brandt, P. C.
The periodicities of energetic neutral atoms (90-170 keV oxygens) at Saturn are determined by applying Lomb-Scargle periodogram analyses to energetic neutral atom (ENA) fluxes observed in eight local time sectors of the equatorial plane between 5 and 15 RS (1 RS = 60,268 km). The analyses come from four long intervals (>18…